@article{Schulten:1976:RE,
author = {Schulten, K. and Gordon, R. G.},
title = {Recursive evaluation of $3j$- and $6j$- coefficients},
journal = {Comput. Phys. Comm.},
fjournal = {Computer Physics Communications},
year = {1976},
volume = {11},
number = {2},
pages = {269–278},
note = {Double-precision Fortran provided in 3 parts, $j_1$-recursion for $3j$-coefficients,
$m_2$-recursion for $3j$-coefficients, and $j_1$-recursion for $6j$-coefficients},
doi = {10.1016/0010-4655(76)90058-8},
links = {\URL[Code 1]{http://cpc.cs.qub.ac.uk/summaries/ACWQ},
\URL[Code 2]{http://cpc.cs.qub.ac.uk/summaries/ACWR},
\URL[Code 3]{http://cpc.cs.qub.ac.uk/summaries/ACWS}}}